Efficacy of invasive plant powders and inert dusts against Sitophilus zeamais (Motschulsky) in wheat grain

Cereal grain insect pests, specifically Sitophilus zeamais, pose significant challenges to farmers and distributors worldwide, leading to substantial economic losses. Traditional pest control methods often rely on fumigants, raising environmental and health concerns. As an alternative, this study explores the efficacy of unconventional repellents derived from five invasive plant species powders and inert dusts such as wood ash, quartz sand, and zeolite in controlling S. zeamais infestations. The study employs laboratory experiments to evaluate the repellent effects of these substances on adult weevils and progeny emergence on wheat grain under different environmental conditions. Results indicate that plant powders showed some repellent effect (average significant difference in live weevil counts between treated and untreated grain was 13.4 %) and mortality rate (mostly around 20 %), but they were less effective compared to the well-known substances such as SilicoSec® and wood ash (both over 80 % mortality). Similar effects were observed in the progeny emergence experiment. Despite the lower effectiveness compared to conventional substances, the combined application of plant powders with other low-risk methods like the decreasing of temperature and humidity may offer viable pest management strategies in certain scenarios. Additionally, the study underscores the need for further exploration of alternative plant species and the potential for synergistic effects when combining repellent substances.